Amith Singhal, Google's now-retired head of search

Amit Singhal, Google’s head of search, has announced his retirement via social network Google+. Regarded as a brilliant engineer and talented manager, Mr Singhal has been no less than pivotal to the company’s continued success.

He is to be replaced by the Google’s head of AI, and says he intends to dedicate more time to his family and the world of philanthropy.

One of a group of select Indian-born executives with powerful roles at Google, Mr Singhal has been with the company since 2000. He joined as employee number 176.

Singhal was one of the key engineers involved in creating Google search, rewriting and improving the very first algorithms developed by co-founders Larry Page and Sergey Brin.

He is also widely renowned for his role in creating Google Ad Words. The pay-per-click advertising service, Google’s prize money-making machine, brought in an annual revenue of around $50 billion in 2012.

In 2006 he was awarded the title of “Google Fellow” for his work in the company.

He spoke of his pride on leaving Google as the top search provider in the world: “The fact that more than a billion people rely on the Google search prides me. Fifteen years ago I didn’t imagine a single tap on the button would give me a lot of answers.”

In recent years, Mr Singhal’s work on the transition to smartphone tech is seen as crucial in maintaining the company’s market position.

Until now he ranked as one of many high-powered Indian executives at the tech giant. Among his contemporaries were Vic Gundotra (head of Google+) and Nikesh Arora (head of revenue). Both left some time ago. With Singhal’s departure, now only Sundar Pichai, Google CEO, remains at the firm.

Singhal’s replacement has been named as John Giannandrea, up until now Google’s head of artificial intelligence research.

Many see the installing of Giannandrea as a further step towards the intelligent technologies of the future. The new head of search has handled projects including image searching and tagging for pictures and has led the way in getting machine intelligence into new products and apps.